Neuropeptide Y receptors from calf brain : Effect of crude Conus venom preparations on [3H]NPY binding

• Published in: Neurochemistry international Vol. 29; no. 6; pp. 669 - 676
• Main Authors: CZERWIEC, E, DE BACKER, J.-P, VAUQUELIN, G, VANDERHEYDEN, P. M. L
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier 01-12-1996
• Subjects: Animals; Binding, Competitive; Biological and medical sciences; Cattle; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; Frontal Lobe - drug effects; Frontal Lobe - metabolism; Fundamental and applied biological sciences. Psychology; Hippocampus - drug effects; Hippocampus - metabolism; Logistic Models; Mollusk Venoms - pharmacology; Neuropeptide Y - metabolism; Radioligand Assay; Receptors, Neuropeptide Y - drug effects; Receptors, Neuropeptide Y - metabolism; Tritium; Vertebrates: nervous system and sense organs; Neuropeptide Y; Central nervous system; Ox; Gastropoda; Vertebrata; Mammalia; Venom; Peptidergic receptor; Artiodactyla; Invertebrata; Mollusca; Ungulata; Brain (vertebrata)
• ISSN: 0197-0186; 1872-9754
• DOI: 10.1016/S0197-0186(96)00066-6

NPY receptors are identified in calf frontal cortex and hippocampus membrane preparations by binding of N-[propionyl-3H] neuropeptide Y. Saturation and competition binding data with PYY, NPY-(18-36) and NPY itself fit with a single class of sites: for the radioligand KD = 1.4 +/- 0.5 nM, Bmax = 434 +/- 180 fmol/mg protein in frontal cortex, KD = 0.7 +/- 0.2 nM, Bmax = 267 +/- 50 fmol/mg protein in hippocampus. Competition curves of the Y1-subtype selective agonist [Leu31, Pro34]NPY are biphasic in both membrane preparations: high affinity sites (i.e. Y1-subtype) amount to 80% in frontal cortex and 23% in hippocampus. The remaining sites are of the Y2-subtype. Out of 23 Conus venom preparations, 17 inhibit the binding of [3H]NPY in both membrane preparations, but only two of them (from Conus aulicus and C. pennaceus) do so with high potency (IC50 < 5 micrograms protein/ml). Only one venom preparation (from C. mercator) had weak discriminatory properties (IC50Y2/IC50Y1 = 6). Venom from C. anemone increased the [3H]NPY binding 5-fold and with an IC50 of 15-18 micrograms protein/ml. This binding occurred to the venom itself and was unrelated to the NPY receptors since it was equally potent when displaced by [Leu31, Pro34]NPY, NPY-(18-36), PYY and NPY.